1. Field of Invention
The present invention pertains to two-chamber extracting blowers that separate liquid and solid contaminants from a supply of and provide a supply of clean air moving at high velocity air.
2. Description of the Related Art
Blowers for providing air flow are well known. Also well known is the obstacle of heavier-than-air contaminants in the air intake and the desire to remove those contaminants before outflow, particularly as such contaminants can be damaging to downstream equipment. The prior art includes two-chamber extracting blowers that separate contaminants from an intake supply and provide a supply of clean air moving at high velocity. These blowers typically function by rotating an impeller within a divided housing, which draw air axially into the housing and across the blades of the impeller and use the centrifugal effect of the blades to separate the air from the heavier contaminants. In operation, the construction of the blades of the impeller create an area of low pressure that draws air into the blower. Once drawn into the blower, the rotation of the blades causes the air to be forced radially outward between the blades. The air having little or no contamination is quickly forced to the edge of the blades before that air can pass axially into the second chamber within the housing. Air carrying contaminants and having momentum from being drawn into the blower continues axially moving into the second chamber and is redirected by the rotation of the blades in that second chamber, causing the air and contaminants to be directed to the exterior of the second chamber, wherein the contaminants are expelled. This construction has shortcomings, including blade maintenance, noise generation, and effectiveness.
Prior attempts to overcome these shortcomings have included notching the outer edge of the impeller blades to extend about the housing divider or partition separating the first and second chambers (the clean and dirty air chambers). While reducing the contaminant-free air lost to the second chamber, this construction can impede the motion of contaminant-bearing air to the second chamber and precludes removal of the impeller without simultaneous removal of the partition. Impeller removal can be of significant importance when trying to maintain clean blades so as to promote direction of contaminant-free air.
Other prior art attempts have utilized a wiper welded to each blade to guide contaminants to the second chamber. However, because contaminant-bearing air necessarily is flowing over and impacting the weld, the weld surface can become pitted and subject to abrasion. Moreover, as the weld is contacted by corrosive contaminants, the weld is further weakened, causing the cracks inherent in a weld to propagate.
Other prior art attempts have attempted to use wiper-free blades in an impeller notch about the chamber partition in conjunction with an third chamber formed on the outer edge of the first chamber to skim the air of the first chamber for lighter contaminants and heavier contaminants which did not pass to the second chamber are separated from the volume of “clean” air exiting the blower and to cause the contaminants in the air to be ejected with the contaminant-bearing air. This construction, however, requires the addition of components to the housing.
Other prior attempts have attempted to affix a wiper to each blade of an impeller notch about the chamber partition and to construct the blades of the impeller to provide differing cross-sectional areas for the portions of each blade in the first and second chambers to provide pressure differentials between the two chambers. Thus, in addition to shortcomings of a wiper-based impeller, the impeller cannot be easily removed.
Thus, there is a need in the art for an impeller for use in an two-chamber contaminant-extracting blower which operates efficiently and more quietly, permits ease of access and removal of the impeller, avoids welds and additional parts, and generates a pressure differential between the two chambers.